Objective To study the feasibility,effectiveness and safety of temporary pacing at the right ventricular outflow tract area in patients with inferior acute myocardial infarction(AMI)and two or three degree atrioventricular block(AVB). Methods Ninety-five patients with inferior AMI and two or three degree AVB admitted into Cangzhou People's Hospital were randomly divided into right ventricular apex pacing group(47 cases) and right ventricular outflow tract region pacing group(48 cases). Seldinger method was used to perform the right femoral vein puncture in which a 6F sheath tube was placed,and a diode temporary pacing electrode was introduced into it in the two groups. Under the X-ray guidance,in the right ventricular apex pacing group,the electrode was pushed from the inferior vena cava to enter into the right atrium,then cross the tricuspid and finally reach the right ventricular apical portion pacing. In the right ventricular outflow tract region pacing group,under the X-ray guidance, after the electrode was withdrawn and rotated slightly clockwise,it was sent forward to the right ventricular outflow tract region pacing. The duration from the puncture at the right femoral vein to the implanted electrode reaching the pacing region,the pacing threshold,the un-favorable pacing,the incidence of ventricular arrhythmia and prognosis were observed in the two groups. Results The pacing time and pacing threshold in right ventricular apex pacing group were obviously higher than those in the right ventricular outflow tract region pacing group〔pacing time(s):336±150 vs. 354±152,pacing threshold(V):0.9±0.4 vs. 0.7±0.3,both P<0.05〕. The mortality in intensive care unit (ICU)〔0(0/48)vs. 2.13%(1/47)〕,the incidence of bad pacing〔10.42%(5/48)vs. 17.02%(8/47)〕and ventricular fibrillation(VF),sustained ventricular tachycardia,contraction of non-sustained ventricular tachycardia or frequent ventricular premature beat(VPB)and other arrhythmia incidence of complications〔10.42%(5/48)vs. 12.77%(6/47)〕in the right ventricular outflow tract region pacing group were all lower than those in the right ventricular apex pacing group. Conclusion The application of right ventricular outflow tract pacing in patients with inferior AMI and two or three degree AVB is safe and effective,and its stability is fine.

RNA interference(RNAi)is a process by which introduced small interfering RNA(siRNA)can cause the specific degradation of mRNA with identical sequences. The human herpes simplex virus type 1(HSV-1)RR is composed of two distinct homodimeric subunits encoded by UL39 and UL40, respectively. In this study, we applied siRNAs targeting the UL39 and UL40 genes of HSV-1. We showed that synthetic siRNA silenced effectively and specifically UL39 and UL40 mRNA expression and inhibited HSV-1 replication. Our work offers new possibilities for RNAi as a genetic tool for inhibition of HSV-1 replication.